linux-kernel - Re: mm: mmu_gather: do not expose delayed

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Message-ID: <CAHk-=win6sosEYKi1HcmEFDVH8S4cWntb1RH1z_=Tbkk45ZTLA@mail.gmail.com>
Date:   Wed, 16 Nov 2022 09:45:04 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Alexander Gordeev <agordeev@...ux.ibm.com>
Cc:     Hugh Dickins <hughd@...gle.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Nadav Amit <nadav.amit@...il.com>,
        Will Deacon <will@...nel.org>,
        Aneesh Kumar <aneesh.kumar@...ux.ibm.com>,
        Nick Piggin <npiggin@...il.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
Subject: Re: mm: mmu_gather: do not expose delayed_rmap flag

On Tue, Nov 15, 2022 at 11:49 PM Alexander Gordeev
<agordeev@...ux.ibm.com> wrote:
>
> Flag delayed_rmap of 'struct mmu_gather' is rather
> a private member, but it is still accessed directly.
> Instead, let the TLB gather code access the flag.

Now, I set it up so that if you don't use delayed_rmap, the
tlb_flush_rmaps() function ends up being an empty inline function, and
as such the compiler should already have done this for you - including
optimizing out the test that then doesn't even matter.

But this patch shouldn't *matter*, but it also isn't wrong, so..

Acked-by: Linus Torvalds <torvalds@...ux-foundation.org>

Thanks,

                    Linus